In a large bowl, beat the butter, brown sugar, and molasses until soft and fluffy. Whip in the pumpkin puree, vanilla extract, and egg.
In a separate bowl, whisk together 2 cups of flour, baking soda, 2 teaspoons of cinnamon, 1 teaspoon of ginger, cloves, allspice, nutmeg, and salt. Add dry ingredients to the wet and beat until just combined. The dough will be quite sticky but should be cohesive. If it's too sticky, add flour 1 tablespoon at a time, beating in between each addition until just incorporated. I used 2 1/3 cups but you may need up to 2 1/2 cups depending on your location and climate. Cover the bowl and chill for 30 minutes, or up to overnight.
Preheat oven to 350 degrees and line two large baking sheets with parchment. Toss together the sugar and remaining teaspoon each of cinnamon and ginger in a small bowl. Remove the dough from the fridge. Scoop approximately tablespoon-sized balls of dough and, one at a time, toss in the cinnamon-ginger sugar. Set onto the baking sheets about 3 inches apart. Bake 10-12 minutes until the edges are set. Let cool on the baking sheet for 5 minutes, then move to a wire rack to cool completely.